function show_div(id)
{
	var alphabet = ["norma","diva","divb","divc","divd","dive","divf","divg","divh","divi","divj","divk","divl","divm","divn","divo"];
	for(i=0;i<16;i++)
	{
		if(alphabet[i]!=id)
		{
			document.getElementById(alphabet[i]).style.display = "none";	
		}
		else
		{
			document.getElementById(alphabet[i]).style.display = "block";
		}
	}
}